Effect of salicylic acid application on quantitative and qualitative features of ‎Ziziphora clinopodioides Lam. under water deficit stress condition

In order to study the effects of water deficit stress and salicylic acid application on morphological and physiological characteristic of Ziziphora clinopodioides Lam. a factorial experiment based on a complete randomized block design with four water deficit stress levels (100%, 75%, 50% and 30% FC) and three levels of salicylic acid (0, 0.5 and 1 mM) in three replications was performed in greenhouse condition. Water deficit stress decreased plant, leaf and stem dry weight, leaf area, chlorophyll a, b and total chlorophyll content, carotenoids content and essential oil yield, while these traits increased by application of SA. Total phenol content was increased by water deficit stress and SA application. The highest level of plant (18.2g), leaf (6.6g), and stem (8g) dry weight were observed in 100% FC with 0.5 mM SA. Essential oil yield was decreased by water deficit stress and the highest level of this character was obtained in 100% FC with 0.5 mM SA application. According to the obtained results, Z. clinopodioides needs to irrigate at field capacity along with  0.5 mM SA in order to reach to the highest growth and chemical yields.